1. Field of the Invention
This invention relates to orifice fittings for measuring the flow of fluids, including oil, gas, water and slurries in pipelines. More particularly, the invention includes a multi-orifice plate located in a specially designed orifice fitting and coupled to a plate positioning and differential selector mechanism for automatically mechanically adjusting the multi-orifice plate vertically inside the orifice fitting by pressure differential. Recording meters are also provided, each having an appropriate scale for reading and recording the differential pressure across the respective orifices in the multi-orifice plate, responsive to operation of the plate positioning and differential selector mechanism.
Conventional orifice fittings facilitate removal of orifice plates having a single orifice from the line bore of the orifice fitting without terminating flow of the fluid through the pipeline. These orifice fittings are typically provided with dual-chambers which allow the orifice plates to be removed safely and conveniently in a pressurized pipeline without reducing or terminating the pressure in the pipeline. Removal and replacement of the respective single orifice plates to effect alignment of an orifice of appropriate size in the fluid flowing through the pipeline is typically effected by operation of a rack-and-pinion-operated, stainless steel slide valve which, when closed, separates the dual chambers in the orifice chambers. The slide valve cannot be closed unless the orifice is properly located in the upper chamber of the orifice fitting and the valve may be easily opened and closed from outside the orifice fitting to effect the desired orifice plate change. Other conventional orifice fittings include single chamber fittings and both the single and dual chamber orifice fittings require periodic removal and replacement of the respective orifice plates to facilitate presentation of an orifice of selected size in the line bore and compensate for pressure fluctuations of the fluid in the pipeline in which the orifice fitting is mounted.
2. Description of the Prior Art
Typical of the single and dual chamber orifice fittings known in the art are the "Superior" (trademark) orifice fitting marketed by Superior Measuring Equipment Company of Houston, Tex.; "C-E Invalco Master Orifice Fittings" (trademark) marketed by Combustion Engineering of Tulsa, Okla.; "Peco" (trademark) orifice fittings marketed by Perry Equipment Corporation of Mineral Wells, Tex.; and "Daniel" (trademark) orifice fittings marketed by Daniel Industries, Inc., of Houston, Tex. The orifice fittings marketed by these companies are characterized by single and dual chamber designs, as described above.
It is an object of this invention to provide a new and improved orifice fitting which is designed to receive a multi-orifice plate and a positioner and differential selector system for automatically sensing changing pressure conditions in the line bore of the orifice fitting, changing orifice sizes by vertical orifice plate adjustment in the orifice fitting and selecting a recording meter having an appropriate recording scale for recording differential fluid pressure across the orifice located in the line bore of the orifice fitting.
Another object of this invention is to provide a new and improved multi-orifice plate having a mechanical, valve-operated positioner and differential selector mechanism for vertically adjusting the multi-orifice plate in a modified orifice fitting to present the proper orifice in the fluid flow stream for pressure measurement by a recording meter having a scale corresponding to the pressure differential of the fluid flowing through the orifice and line bore of the orifice fitting.
Still another object of this invention is to provide a multi-orifice plate for vertical and adjustable mounting in a specially designed orifice fitting and a pressure selector valve, meter valve, and recording meter and plate piston system coupled to the multi-orifice plate, wherein the pressure selector valve operates to sense a change in pressure of the fluid flowing through the line bore of the orifice fitting, and in connection with the meter valves and plate piston, facilitates vertical adjustment of the orifice plate alignment to position an orifice of selected size in the line bore and selection of a recording meter having an appropriate recording range for recording the pressure differential across the orifice.